Engineering Drawing part-4

CH-1  Drawing instruments and their uses

Scale

1- Scale is a measuring instrument by which we measure the distances .

2- It is made of wood ,steel,celluloid or plastic or card board.

3- Stainless steel scale are more durable .

4- Scales are (15 cm long and 2 cm wide ) or  (30 cm long and 3 cm wide )

5- Scales are in common use  is 1 mm thick.

6- The card board scale are available in a set of 8 scales
 













Protractor

1- protractor  of transparent  celluloid are common use ..

2-It is also made of wood and tin.

3- They are flat and circular and  or semicircular in shape.

4- It  have 0 - 180  degree angle presentation in both sides 

5- Its center o is mention at that point 90 degree exist at the top 


Protractor 












Drawing Paper

1- Drawing paper are available in many varieties

2- For ordinary pencil drawing the paper selected should be tough and strong

3-It should be uniform in thickness and have good whiteness

4- when the  rubber eraser are used on the paper it fibers should not disintegrate


 Note-Size  of drawing papers are given bellow 

 A 0  (841 mm x 1189 mm)

A 1  (594 mm x 841 mm)

A 2  (420 mm x 594 mm)

A 3  (297 mm x  420 mm)

A 4  (210 mm x 297 mm)

A 5  (148 mm x 210 mm)




















Decreasing order  of size is given as-

A0 > A1 >A2 > A3> A4> A5

A0 is big size 
A5 is small size


Drawing Pencil        

  (H ,2H,3H,4H)etc

1- The quality and appearance  of a drawing depend upon the quality of pencils used

2-  Beginning  of a drawing should be made with  H or 2H pencil ,using it very  lightly 
  because of after drawing extra lines can be erase easily

3- H and HB  pencils are more suitable for lettering and dimension 



Eraser

1-Soft rubber is the most suitable Eraser for pencil drawing.

2- It does not spoil the surface of the paper.



Duster

 Duster should be used for cleaning the surface to drawing board before we start the drawing

If duster not available then we use piece of towel


Drafting machine

1- Drafting machine is  called  MD in  short 

2-In this machine T-Square , Set Square, Scales and Protractor are assembled 

3- By the help of this machine we draw Horizontal, vertical  lines with accuracy 

4-It is the main instrument of drawing in drawing board


  Drafting machine







For Engineering Drawing part-5  click link




For Engineering Drawing part-3 click link






















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